1. Field of the Invention
The present invention relates to a plant monitor-control apparatus which monitors and controls a plant.
2. Description of the Related Art
In general, a plant monitor-control apparatus includes a control device which controls a device to be controlled in a plant, and an operation/monitor device. An operation instruction is delivered from the operation/monitor device to the plant via the control device. Thereby, the to-be-controlled device of the plant is operated, and the plant is monitored.
FIG. 39 is a block diagram showing an example of the plant monitor-control apparatus. In FIG. 39, a plurality of control devices 2 to 2n and a plurality of operation/monitor devices 3-3n are connected to a network 1. A to-be-controlled device 4 is connected to each of the control devices 2 to 2n. FIG. 39 shows the case in which the to-be-controlled device 4 is connected to the control device 2.
In the plant monitor-control apparatus with the above structure, the to-be-controlled device 4 is operated by any one of the operation/monitor devices 3 to 3n. In this case, an operation instruction from the operation/monitor device is sent to one of the control devices 2 to 2n via the network 1. In FIG. 39, the operation instruction is output from the control device 2 to the to-be-controlled device 4. The state information of the to-be-controlled device 4 is input to the control device 2 from the to-be-controlled device 4, and is displayed on the operation/monitor device, 3-3n, via the network 1.
As regards the security in this plant monitor-control apparatus, in general, switching from a prohibition state to a permission state or from the permission state to the prohibition state can be executed by inputting a password for operation permission/prohibition in the system. In addition, the permission/prohibition of the device operation can be switched in units of an operation/monitor device.
There is a technique in which various data and operation/monitor information, which are handled by a control device, are monitored, and abnormality is reported to a plant operation/monitor device (see, e.g. Patent Document 1).    Patent Document: Jpn. Pat. Appln. KOKAI Publication No. 9-189582